Generator



May l, 1945' H. L. BONE ETAL 2,374,728

GENERATOR Original Filed Jan. 4, 1941 Fig!! u E? ATTOR N EY Patented May 1, 1945 UN ITED .f STATES- PAT'ENT OFFICE GENERATOR Herbert L. Bone, Forest Hills, Pa., and John W. Livingston, Milwaukee, Wis., assigors t`o` Tlvie Union' Su'fitchV and Signal Company; SWis'svale, Pa., a corporation of Pennsylvania (Cl. lue-209) 3 Claims.-

Our invention relates to generators, and particularly tov generatorswhich are intended to be mountedl on thejournal boxes, and driven from the ax-les, of cars or locomotives. which are in high speed servicev for indicating or controlling the speed of the cars or locomotives, for controlling the braking ratio, or the like.

One object of our invention is to provide an improved permanent magnet field assembly `for a generator' of the type described which assembly is suiicientlyruggedA to stand up under the severe operating conditions to which the generator is subjected, and which can be manufactured at a minimum cost.

According to our invention, the eld assembly of the generator comprises a pair of permanent l magnets clamped between pole pieces by means of -socket head cap screws of non-magnetic mate rial. The bore in the generator housing and outside diameter of the i'leld assembly are accurately machined so that the lield assembly will have a light press t with the housing. This iit, while sufficiently-snug to hold the assembly in place, is not ltight enough to set up undesirable stresses Yin the permanent magnets. The field assembly isclamped between the body and one end bell of the generator housing by means of suitable bolts passing through clearance holes in the pole pieces and threaded into tapped holes in the body casting.

Other objects and characteristic features of our invention will become apparent as the description proceeds.

The present invention is a division of our copending application, Serial No. 373,132, led on January 4, 1941, now Patent No. 2,313,916 of Mar. 16, 1943, for Generator and mounting means therefor.

We shall describe one form of generator embodying our invention, and shall then point out the novel features thereof in claims.

In the accompanying drawing, Fig. l is a vertical sectional view showing a generator provided with a field assembly constructed in accordance with our invention. Fig. 2 is a sectional View taken substantially on the line II-II of Fig. 1.

Similar reference characters refer to similar parts in both views.

Referring to the drawing, a generator embodying our invention comprises, as usual, an armature A and a eld assembly F disposed within a suitable housing I. This housing as shown consists of a main body portion I a provided at one end with an end cap lb and at the other end with an end bell Ic.

The armature A is of conventional construction, and` is rotatably mounted in suitable antifriction bearings 2 and 3 secured. within` bearing openings 4 and 5 formed respectively in a bearingI and brush support ld provided on the main body portion la and in-an end bell lc. The armature commutator 6` is` disposed within the support Id andcooperates with brushes not shown-mountedr in brush-holdersl secured to thesupport.V The construction of the brushes and brushY holders forms no part of our present invention, and hence neednot be specifically described.

The eld assembly of. the generator,y whicheld assembly embodies our invention, consists of'magnetizable pole pieces l0 and Il, preferably of cold rolled steel, and permanent magnets l2 which are clamped between the pole pieces on opposite sides of the armature by means of two socket head cap screws 8 of non-magnetic material. The pole pieces are provided with curved pole faces lila and lla for cooperation with the armature, and with recesses lb and Hb which receive the ends of the magnets to retain them in the proper posi tions and to provide a good magnetic connection between the permanent magnets and the pole pieces. It will be noted that the permanent magnets are in the form of rectangular bars which eliminates any necessity for machining the magnets, whereby the cost of construction of the held assembly is reduced to a minimum.

The iield assembly is disposed within a bore le formed in the main body portion la of the housing l, and this bore and the cooperating outer surfaces ofthe pole pieces are accurately machined to provide a press t between the field assembly and the housing. This t, while suiliciently tight to snugly hold the iield assembly in place, is not tight enough to set up undesirable stresses in the magnets.

The iield assembly in addition to being held in place by a press t between it and the housing is clamped between a shoulder if formed in the body at the inner end of the bore Ec and the end bell Ic fby means of four bolts E3 which pass only one form of generator embodying our inscope of the appended claims Without departing from the spirit and scope of our invention.

Having thus described our invention, what We rclaim is:

1. A field assembly for a generator or motor having a housing provided With a Ibore for the reception of the assembly, said assembly comprising a pair of pole pieces each provided with a pole face and with a recess disposed on each side of said pole face, a pair of straight magnets clamped between said pole pieces with their ends disposed in said recesses, said pole pieces in their assembled positions having their outer surfaces accurately machined to fit into the bore of said housing with a press nt which is sufficiently tight to snugly hold the field assembly in place but not tight enough to set up undesirable stresses in the magnets.

2. A eld assembly for a generator or motor having a housing provided with a bore for the lreception ofthe assembly, said assembly comprisnot tight enough to set up undesirable stresses in the magnets, andA bolts passing through clearance holes provided in the pole pieces and screwed into tapped holes provided in the housing.

3. A field assembly for a generator or motor having a housing provided with a bore for the l to snugly hold the field assembly in place :but not tight enough to set up undesirable stresses in the magnets, a shoulder disposed at the inner end of said bore and engaging the inner sides of said pole pieces, an end bellfor the generator or motor engaging the outer side of said pole pieces, and bolts passing through clearance holes provided in said end bell and said pole pieces and screwed into tapped holes provided in the housing, said bolts serving both vas a means for securing said end bell in place and also as a means for clamping said iield assembly between said shoulder and said end bell.

HERBERT L. BONE. JOHN W. LIVINGSTON. 

